The EPPA prohibits most private employers from using lie detector tests, either for pre-employment screening or during the course of employment. Employers generally may not require or request any employee or job applicant to take a lie detector test, or discharge, discipline, or discriminate against an employee or job applicant for refusing to take a test or for exercising other rights under the Act. Employers may not use or inquire about the results of a lie detector test or discharge or discriminate against an employee or job applicant on the basis of the results of a test, or for filing a complaint, or for participating in a proceeding under the Act. Subject to restrictions, the Act permits polygraph (a type of lie detector) tests to be administered to certain job applicants of security service firms (armored car, alarm, and guard) and of pharmaceutical manufacturers, distributors and dispensers.

Subject to restrictions, the Act also permits polygraph testing of certain employees of private firms who are reasonably suspected of involvement in a workplace incident (theft, embezzlement, etc.) that resulted in specific economic loss or injury to the employer. Where polygraph examinations are allowed, they are subject to strict standards for the conduct of the test, including the pretest, testing and post-testing phases. An examiner must be licensed and bonded or have professional liability coverage. The Act strictly limits the disclosure of information obtained during a polygraph test.

The regulations implementing the 1988 EPPA may be found at 29 CFR 801.